Lee G. Partridge took over the role of chief investment officer of The Endowment Fund from Mark W. Yusko as part of a shake-up of investment control of the $3.1 billion fund.

The manager-of-managers fund is a 9-year-old joint venture between Morgan Creek Capital Management, of which Mr. Yusko is CEO and CIO, and Salient Partners, of which Mr. Partridge is managing director and CIO. About 15% of fund investors are institutions, with the balance mainly high-net-worth individuals.

Mr. Yusko was “removed” as CIO because “recent post-crisis returns have been underwhelming” and redemption requests indicate “that a meaningful number of investors have lost confidence in Mr. Yusko's ability to deliver results consistent with expectations and we believe a change is warranted,” according to a Tuesday investor letter from Endowment Advisers, which runs The Endowment Fund, that was obtained by Pensions & Investments. The letter did not provide recent performance of The Endowment Fund.

In his own letter Tuesday to Morgan Creek Capital Management investors that was obtained by P&I, Mr. Yusko said he “relinquished” his role as CIO of The Endowment Fund.

“After nearly a decade of working with our joint venture partner … we found ourselves differing on material aspects of how to best run an endowment portfolio and run the business, so we decided that a change was appropriate,” Mr. Yusko wrote.

In October, Endowment Advisers limited withdrawals from the fund to 5% of invested assets. A source who asked not to be identified said about 13% of investors requested redemptions by year-end.

The Endowment Advisers investor letter said the year-end redemption will be paid by Feb. 15 and a second 5% withdrawal for the quarter ended March 31 was approved by The Endowment Fund's board of directors. The Endowment Fund is closed to new investment or reinvestment by existing investors who took a withdrawal, but will reopen to investment on March 1, the letter said.

Mr. Partridge, who was chief portfolio strategist of the fund, has assumed day-to-day investment management of the fund and will implement a plan to “improve the performance and the liquidity profile of the fund,” the Endowment Advisers' letter said.

The investment strategy change will seek to increase the risk-adjusted returns while targeting portfolio volatility about half that of equity markets, and Mr. Partridge will substitute lower-cost investment strategies and will make larger, more concentrated allocations to a smaller number of hedge fund managers, particularly in global macro and relative value strategies, the letter said.

Under Mr. Yusko's tenure, The Endowment Fund had a significant percentage invested in illiquid asset classes such as private equity, real estate and energy/natural resources. The Endowment Advisers investor letter did not provide the current or target allocation to these asset classes under the new investment plan, but did say the current investments “will be an important driver for the fund in the future as the portfolio continues to mature.”

The letter went on to note that Mr. Yusko will remain on the investment committee of Endowment Advisers and the ownership and revenue sharing arrangement between Morgan Creek Capital Management and Salient Partners remains intact. Terms of the joint venture arrangements were not provided in the Endowment Advisers' letter.

Officials at Salient Partners declined to comment, said Christina Moon, a spokeswoman for the company. Salient Partners managed about $17.8 billion as of Aug. 31, according to its website.

Mr. Yusko was traveling and unavailable for comment, said Douglas Hesney, a Morgan Creek spokesman. Mr. Hesney could not provide Morgan Creek's AUM.